As an execise science lecturer - no catcalls please - do as I say not as I do rules my classroom
- I would say that you are in the moderate range there!
Meg has given you a good idea of how to measure your intensity - depending on a long list of individual variables! But the general rule of thumb is - if you can say your phone number (incl. dialling code) then you are NOT PUSHING IT to a high intensity.
BUT... and here's the science bit... that is EXACTLY where you need to be to get the best results. Remember your physics ("Oh yes, Stef", I hear you cry, "we all do don't we"
effort x time = work done!
So if you put in a BIG effort for a short amount of time then your work done will be quite low - so a 20 second flat out sprint will only give you so many calories. BUT if you move at a slightly
lower pace you will be able to move for a lot
longer - so your work done will increase!
It really is that simple - think of it like this - how far can you move your body?
Effort = your body weight
Time = how long or how far you keep it moving
Work done = calories
If you change either the length
of time you move at one
speed or the distance
you move in the same
period of time you will have increased the work you do - or calories spent!
e.g. a snail will take a long time to burn the same calories as a cheetah in a sprint - but you probably get the picture! Oh, and please forgive the ultra simplification of the science - but I teach 16 - 19 year olds who think sport science is playing football all day!!!!!
Move as fast as is doable for 40 - 60 minutes. You will find that you will travel further in that same time - thereby increasing the work done without having to break anything!
Your description of increased temperature and breathing rate is a good indication that you are working quite well - just don't be tempted to move so fast that you cannot say your phone number out loud - that is for later, when you want to be an elite runner
Hope I didn't bore anyone too much - but I am currently writing up a lesson on exercise intensities - and thought I'd let a little bit leak out....